Scale Broken or Normal Fluctuations?

I have been working on a weight lose goal. However my weight seems to be fluctuating day to day. Do you think I have a broken scale or is this actually possible to have this level of fluctuations?


Weight does indeed fluctuate day to day. The fluctuations on your graph seem on the large side, but still within the realm of normal/possible. It seems unlikely to me that a scale could be broken in such a way as to still give plausible results but with extra fluctuation added in. To test it you could try doing several weighings in a row, say, within 5 or 10 minutes of each other. If you are still getting results that differ by several pounds even when weighing yourself twice within 5 minutes, then we could perhaps conclude there is something wrong with your scale.


@linux535: I also track my weight.

3 suggestions for data consistency:

  1. Wear the same type of clothes every weigh in. I personally weight myself with the same 2 or so pajama pants every day.

  2. Check your weight around the same time or so every day. I typically check mine around 10 AM. It is crazy how much your weight can fluctuate if you do not track it at the same time. For example one time I checked my weight at 5 AM in the morning because I had a flight. It was a 3 pound difference from the day before.

  3. It may be useful to export your data into a spreadsheet so that you can check the average. Really the average is what matters week to week, month to month.


One thing that has produced some pretty wild errors for me is… making sure my scale is zeroed properly every time before I step on it. :sweat_smile: Impatience doesn’t serve here, so now I make sure to put it down in the same spot with all four feet stable, on a hard surface, and then zero it. Once it’s properly zeroed, then I weigh myself.

This may not matter with all brands of scale, of course, but for some it does need to zero itself and it isn’t obvious that’s what it’s doing. Mine does it as it turns on, and it’s important that it’s flat on the ground as it starts doing that, rather than me still moving it around. If it displays the zero before I’ve settled it flat on the floor, I have to make it reset (which involves letting it turn off and then bonking it gently to make it turn on again; look, I didn’t say it was a great scale).


My scale has a zero out function. I am going to start doing that I bet it will fix my problems if there are any.

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When I started losing weight, I would have days where my morning to evening weight would change multiple pounds. Going from even a little dehydrated to having a salty meal at a restaurant would do it to me basically every time.

It was really demotivating, and led to me avoiding salty food and restaurant food, which probably did better things for my health than anything else I was doing at the time :slight_smile:


I’m going to make a, um, indecorous suggestion. Have you been weighing yourself with the same “bathroom status” each day? If you haven’t peed yet that morning and you’re a bigger person (as I am) the fluctuations from that alone can be wild–on the order of 2-3 pounds.

Some other things which can trigger big weight swings:

  • a big workout the day before
  • excessive drinking, especially beer (sometimes 3 beers is enough to cause bloating)
  • poor sleep
  • a normal amount of calories but extra salt (fast food, or decadent meal)

All of these have been enough to cause me to wake up with an extra 2 pounds on the scale, when i know that I didn’t eat 7000 calories the day before.

But that’s why we say to weigh yourself daily! The more data you have, the more the fluctuations can smooth out to something approaching reality. For this reason it’s typically better to look at the moving average (purple line) and check whether it’s trending up or down lately.


As others said, there are plenty of factors : clothes, time of day, poop status, late-night/salty food, etc. I would recommend setting the Beeminder goal with a lot of room for fluctuation and mostly caring/beeminding the trend of the weight.


I get sometimes get fluctuations of over a kilo (2.5lb), which is more than 1% of my current weight, even when weighing in at about the same time of day in the same clothes and with the same, um, bathroom status.

That’s why we recommend setting a shallow (conservative) downward slope on your weight loss goal, and to have other goals that encourage exercise and good eating habits.


Forgot to update weight has stabilized since zeroing out every time.